If you miss your Initial Enrollment Period, you may need to wait for the General Enrollment Period, which runs from January 1 to March 31. People who sign up during the General Enrollment Period will be eligible for coverage the following July. Late enrollment penalties typically apply to people who miss their Initial Enrollment Period. Depending on the Medicare plan you apply for, these penalties can vary from 10% for every 12 months you delay enrollment to 1% per month.

If you’re on Social Security (which you can begin receiving at age 62), then you should be automatically enrolled in Medicare Part A and/or Part B when you turn 65. However, you should check to confirm that this is true—either by contacting Social Security or the Medicare program—or you may incur a late enrollment penalty.

Once you turn 65, Medicare is considered your primary insurer, making other insurance companies your secondary. This is true even if you haven’t applied for Original Medicare yet. It’s also true even if you have retiree health insurance, individual health insurance, or COBRA. It’s important to understand how Original Medicare coverage works if you’re still employed because it means you might not be able to count on your other forms of insurance to pay for your hospital or doctor’s office bills once you turn 65.

If you enroll in Original Medicare and your income is above a certain threshold, you’ll pay more for Parts B and D. Premiums for both parts can come with a surcharge when your adjusted gross income (plus tax-exempt interest) is more than: $109,000 if you are single $218,000 if married and filing jointly In 2026, high earners pay $284.10 to $689 per month for Part B, depending on income level, and they also pay extra for Part D coverage, from $14.50 to $91 on top of the regular premiums.

Original Medicare is an individual benefit, so each member of your family needs to apply for Original Medicare separately. There are no family Medicare plans.

Those new to Original Medicare (and even some who’ve been enrolled for a while) are sometimes surprised to learn that Original Medicare generally does not cover long-term care. However, there are certain circumstances where services related to long-term care may be covered. One example is services needed after a hospitalization from an acute-care event. In this case, Original Medicare will pay for medically necessary skilled nursing facility (SNF) or home health care. However, “custodial care” services that help you with the activities of daily living, like dressing and bathing, are not covered.

There may be an occasion when you don’t agree with an Original Medicare health plan decision about your coverage or payment. In this case, you’re entitled to file an appeal. There are five levels to the appeals process, some of which are settled at lower levels and others taking more time. Be sure to present as much relevant information as you can when you first make your appeal—your physician can help. 

It’s also important to collect any relevant hospital records or information from other providers and/or suppliers. In situations where a decision needs immediate attention, you can request a fast-track decision, which must be made within 72 hours. However, this requires your doctor's and/or your Medicare plan's agreement.